Abstract
Pure κ-casein solutions in concentrations of less than 0.1% produce measurable turbidities in acetate buffer in the presence of dilute rennet solutions at pH 5.8 and 30 C. In mixtures of αs- and κ-casein containing less than 20% κ- the increase in turbidity after 5 min is proportional to the percentage κ-casein in the mixture. Calcium is needed in the reaction mixture (.008M) to bring about the turbidity increases. The turbidity of pure αs-casein is not affected by addition of rennet. Variable increases in turbidity after rennet action on purified β-casein fraction point to the difficulty of separation of κ-casein from β-casein. Isolated whole casein reacts more slowly with rennet than does purifled κ -casein.